Sidelink conflict indication

Abstract

Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may identify a conflict between sidelink messages in one or more sidelink resources of a set of sidelink resources reserved for communications by a second UE. In response to identifying the conflict, the first UE may measure a system load of a sidelink channel for the sidelink messages and may determine a threshold system load of the sidelink channel based on one or more priorities associated with the conflicting sidelink messages. If the system load satisfies the threshold system load, the first UE may transmit a message that indicates the conflict. Additionally, or alternatively, the first UE may transmit the conflict indication using a resource determined based on whether one or more of the conflicting sidelink messages are a broadcast sidelink message or a groupcast sidelink message.

What is claimed is: 
     
       1. A method for wireless communication at a first user equipment (UE), comprising:
 receiving, from a second UE, sidelink control information that indicates one or more sidelink resources reserved for communication by the second UE; 
 measuring a system load of a sidelink channel associated with the one or more sidelink resources based at least in part on a conflict between one or more sidelink transmissions in the one or more sidelink resources reserved for communication by the second UE and one or more other sidelink transmissions; and 
 transmitting a message comprising an indication of the conflict based at least in part on the system load satisfying a threshold system load of the sidelink channel from a set of threshold system loads, wherein the threshold system load is associated with a priority of a sidelink transmission of the one or more sidelink transmissions or the one or more other sidelink transmissions, and wherein the sidelink transmission is associated with a highest priority of the one or more sidelink transmissions or the one or more other sidelink transmissions. 
 
     
     
       2. The method of  claim 1 , further comprising:
 determining the threshold system load of the sidelink channel based at least in part on one or more priorities associated with the one or more sidelink transmissions. 
 
     
     
       3. The method of  claim 2 , further comprising:
 selecting the threshold system load from the set of threshold system loads based at least in part on the priority of the sidelink transmission that is associated with the highest priority. 
 
     
     
       4. The method of  claim 3 , wherein the set of threshold system loads is configured or pre-configured for the first UE, and each of the set of threshold system loads corresponds to a respective priority of a set of priorities for sidelink communications. 
     
     
       5. The method of  claim 1 , further comprising:
 receiving, from the second UE, second sidelink control information that indicates one or more second sidelink resources reserved for communication by the second UE; 
 measuring a second system load of the sidelink channel associated with the one or more second sidelink resources based at least in part on a second conflict between one or more second sidelink transmissions in the one or more second sidelink resources reserved for communication by the second UE and one or more second other sidelink transmissions; and 
 refraining from transmitting a second message comprising an indication of the second conflict based at least in part on the second system load failing to satisfy a second threshold system load of the sidelink channel, the second threshold system load based at least in part on one or more priorities associated with the one or more second sidelink transmissions. 
 
     
     
       6. The method of  claim 1 , wherein measuring the system load of the sidelink channel comprises:
 measuring a channel occupancy ratio associated with the sidelink channel, a channel busy ratio associated with the sidelink channel, or both. 
 
     
     
       7. The method of  claim 1 , wherein the conflict between the one or more sidelink transmissions and the one or more other sidelink transmissions comprises a time overlap between the one or more sidelink resources and the one or more other sidelink transmissions, a frequency overlap between the one or more sidelink resources and the one or more other sidelink transmissions, or both. 
     
     
       8. The method of  claim 1 , wherein transmitting the message comprising the indication of the conflict comprises:
 transmitting the message comprising the indication of the conflict after the conflict has occurred, wherein the indication of the conflict indicates retransmission of the sidelink transmission by the second UE. 
 
     
     
       9. The method of  claim 1 , wherein transmitting the message comprising the indication of the conflict comprises:
 transmitting the message comprising the indication of the conflict prior to the conflict occurring, wherein the indication of the conflict indicates the second UE to refrain from transmitting the sidelink transmission. 
 
     
     
       10. An apparatus for wireless communication at a first user equipment (UE), comprising:
 at least one processor; 
 memory coupled with the at least one processor; and 
 one or more instructions stored in the memory and executable by the at least one processor to cause the apparatus to, based at least in part on the one or more instructions:
 receive, from a second UE, sidelink control information that indicates one or more sidelink resources reserved for communication by the second UE; 
 measure a system load of a sidelink channel associated with the one or more sidelink resources based at least in part on a conflict between one or more sidelink transmissions in the one or more sidelink resources reserved for communication by the second UE and one or more other sidelink transmissions; and 
 transmit a message comprising an indication of the conflict based at least in part on the system load satisfying a threshold system load of the sidelink channel from a set of threshold system loads, wherein the threshold system load is associated with a priority of a sidelink transmission of the one or more sidelink transmissions or the one or more other sidelink transmissions, and wherein the sidelink transmission is associated with a highest priority of the one or more sidelink transmissions or the one or more other sidelink transmissions. 
 
 
     
     
       11. The apparatus of  claim 10 , wherein the one or more instructions are further executable by the at least one processor to cause the apparatus to, based at least in part on the one or more instructions:
 determine the threshold system load of the sidelink channel based at least in part on one or more priorities associated with the one or more sidelink transmissions. 
 
     
     
       12. The apparatus of  claim 11 , wherein the one or more instructions are further executable by the at least one processor to cause the apparatus to, based at least in part on the one or more instructions:
 select the threshold system load from the set of threshold system loads based at least in part on the priority of the sidelink transmission that is associated with the highest priority. 
 
     
     
       13. The apparatus of  claim 12 , wherein the set of threshold system loads is configured or pre-configured for the first UE and each of the set of threshold system loads corresponds to a respective priority of a set of priorities for sidelink communications. 
     
     
       14. The apparatus of  claim 10 , wherein the instructions are further executable by the at least one processor to cause the apparatus to, based at least in part on the one or more instructions:
 receive, from the second UE, second sidelink control information that indicates one or more second sidelink resources reserved for communication by the second UE; 
 measure a second system load of the sidelink channel associated with the one or more second sidelink resources based at least in part on a second conflict between one or more second sidelink transmissions in the one or more second sidelink resources reserved for communication by the second UE and one or more second other sidelink transmissions; and 
 refrain from transmitting a second message comprising an indication of the second conflict based at least in part on the second system load failing to satisfy a second threshold system load of the sidelink channel, the second threshold system load based at least in part on one or more priorities associated with the one or more second sidelink transmissions. 
 
     
     
       15. The apparatus of  claim 10 , wherein the one or more instructions to measure the system load of the sidelink channel are executable to cause the apparatus to, based at least in part on the one or more instructions:
 measure a channel occupancy ratio associated with the sidelink channel, a channel busy ratio associated with the sidelink channel, or both. 
 
     
     
       16. The apparatus of  claim 10 , wherein the conflict between the one or more sidelink transmissions and the one or more other sidelink transmissions comprises a time overlap between the one or more sidelink resources and the one or more other sidelink transmissions, a frequency overlap between the one or more sidelink resources and the one or more other sidelink transmissions, or both. 
     
     
       17. The apparatus of  claim 10 , wherein the one or more instructions to transmit the message comprising the indication of the conflict are executable by the at least one processor to cause the apparatus to, based at least in part on the one or more instructions:
 transmit the message comprising the indication of the conflict after the conflict after the conflict has occurred, wherein the indication of the conflict indicates retransmission of the sidelink transmission by the second UE. 
 
     
     
       18. The apparatus of  claim 10 , wherein the one or more instructions to transmit the message comprising the indication of the conflict are executable by the at least one processor to cause the apparatus to, based at least in part on the one or more instructions:
 transmit the message comprising the indication of the conflict prior to the conflict occurring, wherein the indication of the conflict indicates the second UE to refrain from transmitting the sidelink transmission. 
 
     
     
       19. An apparatus for wireless communication at a first user equipment (UE), comprising:
 means for receiving, from a second UE, sidelink control information that indicates one or more sidelink resources reserved for communication by the second UE; 
 means for measuring a system load of a sidelink channel associated with the one or more sidelink resources based at least in part on a conflict between one or more sidelink transmissions in the one or more sidelink resources reserved for communication by the second UE and one or more other sidelink transmissions; and 
 means for transmitting a message comprising an indication of the conflict based at least in part on the system load satisfying a threshold system load of the sidelink channel from a set of threshold system loads, wherein the threshold system load is associated with a priority of a sidelink transmission of the one or more sidelink transmissions or the one or more other sidelink transmissions, and wherein the sidelink transmission is associated with a highest priority of the one or more sidelink transmissions or the one or more other sidelink transmissions. 
 
     
     
       20. The apparatus of  claim 19 , further comprising:
 means for determining the threshold system load of the sidelink channel based at least in part on one or more priorities associated with the one or more sidelink transmissions. 
 
     
     
       21. The apparatus of  claim 20 , further comprising:
 means for selecting the threshold system load from the set of threshold system loads based at least in part on the priority of the sidelink transmission that is associated with the highest priority. 
 
     
     
       22. The apparatus of  claim 21 , wherein the set of threshold system loads is configured or pre-configured for the first UE, and each of the set of threshold system loads corresponds to a respective priority of a set of priorities for sidelink communications. 
     
     
       23. The apparatus of  claim 19 , further comprising:
 means for receiving, from the second UE, second sidelink control information that indicates one or more second sidelink resources reserved for communication by the second UE; 
 means for measuring a second system load of the sidelink channel associated with the one or more second sidelink resources based at least in part on a second conflict between one or more second sidelink transmissions in the one or more second sidelink resources reserved for communication by the second UE and one or more second other sidelink transmissions; and 
 means for refraining from transmitting a second message comprising an indication of the second conflict based at least in part on the second system load failing to satisfy a second threshold system load of the sidelink channel, the second threshold system load based at least in part on one or more priorities associated with the one or more second sidelink transmissions. 
 
     
     
       24. The apparatus of  claim 19 , wherein the means for measuring the system load of the sidelink channel comprise:
 means for measuring a channel occupancy ratio associated with the sidelink channel, a channel busy ratio associated with the sidelink channel, or both. 
 
     
     
       25. The apparatus of  claim 19 , wherein the conflict between the one or more sidelink transmissions and the one or more other sidelink transmissions comprises a time overlap between the one or more sidelink resources and the one or more other sidelink transmissions, a frequency overlap between the one or more sidelink resources and the one or more other sidelink transmissions, or both. 
     
     
       26. The apparatus of  claim 19 , wherein the means for transmitting the message comprising the indication of the conflict comprise:
 means for transmitting the message comprising the indication of the conflict after the conflict has occurred, wherein the indication of the conflict indicates retransmission of the sidelink transmission by the second UE. 
 
     
     
       27. The apparatus of  claim 19 , wherein the means for transmitting the message comprising the indication of the conflict comprise:
 means for transmitting the message comprising the indication of the conflict prior to the conflict occurring, wherein the indication of the conflict indicates the second UE to refrain from transmitting the sidelink transmission. 
 
     
     
       28. A non-transitory computer-readable medium storing code for wireless communication at a first user equipment (UE), the code comprising instructions executable by at least one processor to:
 receive, from a second UE, sidelink control information that indicates one or more sidelink resources reserved for communication by the second UE; 
 measure a system load of a sidelink channel associated with the one or more sidelink resources based at least in part on a conflict between one or more sidelink transmissions in the one or more sidelink resources reserved for communication by the second UE and one or more other sidelink transmissions; and 
 transmit a message comprising an indication of the conflict based at least in part on the system load satisfying a threshold system load of the sidelink channel from a set of threshold system loads, wherein the threshold system load is associated with a priority of a sidelink transmission of the one or more sidelink transmissions or the one or more other sidelink transmissions, and wherein the sidelink transmission is associated with a highest priority of the one or more sidelink transmissions or the one or more other sidelink transmissions. 
 
     
     
       29. The non-transitory computer-readable medium of  claim 28 , wherein the instructions are further executable by the at least one processor to:
 determine the threshold system load of the sidelink channel based at least in part on one or more priorities associated with the one or more sidelink transmissions. 
 
     
     
       30. The non-transitory computer-readable medium of  claim 29 , wherein the instructions are further executable by the at least one processor to:
 select the threshold system load from the set of threshold system loads based at least in part on the priority of the sidelink transmission that is associated with the highest priority.